Control mechanism for epicyclic gearboxes



G. P. ROBERTS CONTROL MECHANISM FOR AN EPICYCLIC GEAR-BOX Nova 3% 1950 '2 Sheets-Sheet 1 Filed Aug.. 15, 1949 AWE/WM.- GLYN Fiance ROBERTS 6/ Ma; 5'. m

'ITaRA/ f NOV. 14, 1950 ROBERTS 2,529,741

CONTROL MECHANISM FOR AN EPICYCLIC GEAR-BOX Filed Aug. 15, 1949 v 2 Sheets-Sheet 2 Fl 6,4 Fl C. 5

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A-TI'URIVE 7 Patented Nov. 14, 1950 OFFICE CONTROL MECHANISM FOR EPICYCLIC GEARBOXES Glyn P. Roberts, Brewood, England Application August 15, 1949, Serial No. 110,244 In Great Britain August 16, 1948 4 Claims.

This invention relates to a new or improved control mechanism for an epicyclic gear-box.

Normally the selection of a gear is effected by angular movement of a hand-lever over a quadrant having notches or stops for retaining the lever in different positions corresponding to the selection of diiferent gears, a neutral position being provided between bottom gear and reverse positions. The angular movement of the lever effects corresponding angular movement of a cam-shaft in the gear-box so that actuation of the bus-bar by a pedal tightens the band corresponding to the gear which has been selected.

This form of control is quite different from the control for an ordinary layshaft gear-box having what is known as a gate change and is liable to cause a certain amount of difficulty to a driver changing over from one type of control to the other, particularly in the case of a driver of public service vehicles who may be called upon to drive any one of a fleet of difierent vehicles. Further, the total angular movement of the lever is considerable and may be diflicult to accommodate in a drivers cab.

According to my invention the selection of gears in an epicyclic gear-box is effected by means of a hand-lever having the same movements as an ordinary gate change lever, the lever when moved in a direction at right angles to the normal gear-selecting movement being selectively coupled through gearing of different ratios to an angularly movable shaft which is coupled to the cam-shaft in the gear-box so that equal gear-selecting movements of the lever to opposite sides of the neutral position can eifect different angular movements of the camshaft corresponding to the selection of diiferent gears.

lhus the extent of the movement of the lever from a central neutral position to select any one gear is constant and can be made relatively short, and the lever passes through the neutral position in moving from one gear selecting position to another.

One practical form of gear control mechanism in accordance with my invention is illustrated by way of example in the accompanying drawings in which:

Figure 1 is a vertical section of the complete mechanism.

Figure 2 is a vertical section of the mechanism in a plane at right angles to that of Figure 1.

Figure 3 is a diagrammatic plan of the positions of the gear-lever knob corresponding to the selection of the difierent gears.

Figures 4, 5, 6 and *7 are diagrammatic elevations of the movable parts of the mechanism showing the various positions they assume corresponding to neutral and to the selection of the different gears.

Themechanism illustrated is designed for the control of an epicyclic gear-box providing four forward speeds and reverse.

The mechanism is enclosed in a rigid divided housing It of which the two parts are secured together by bolts II and which is adapted to be mounted in any convenient position such as on the floor of the drivers cab of a public service vehicle.

A gear-lever 12 having a knob 13 at its upper end is mounted at an intermediate point in its length for universal movement or for angular movement in two planes at right angle to each other about a spherical boss M in a split socket [5 in the upper part of the housing. At its lower end the lever carries a head It adapted to engage selectively in any one of three forks l1, l8, l9 integral with three parallel toothed segments 29, 2!, 22 of progressively diiferent radius mounted for independent rotation on a spindle 23. The three segments are in constant mesh with complementary segments 24, 25, 26 integral with or keyed on an angularly movable shaft 21 of which the axis is parallel to that of the spindle 23. The shaft 21 is mounted in ball bearings 28 in the housing and one end of the shaft extends from the housing and has splined or otherwise keyed on it a lever arm 29 adapted to be coupled by a link (not shown) to an arm on the camshaft of the gear-box. 1

- The gear-lever I2 is resiliently located in the neutral position and in each of its ear selecting positions by a spring-loaded plunger 39 in the housing co-operating with angularly spaced notches 31 in a quadrant 32 integral with and extending from one side of the lever just above the head I6. Another spring-loaded plunger 3-3 is mounted in one side of the housing in such a position that it has to be pressed in by the quadrant before the lever can be rocked over into a position to select reverse gear.

In the neutral position the axis of the handlever and the head it lie in the plane containing the axes of the spindle 23 and shaft 2? as shown in Figures 2 and 4.

It will be readily appreciated that a rocking movement of the gear-lever in a plane at right angles to the axis of the spindle 23 will move one of the segments 2!), 2!, 22 angularly and so will move the'shaft 2'! and the camshaft of the gearbox angularly through an angle which, for a uniform movement of the lever, depends on which of the forks l1, l8, l9 has been engaged by the head IS on the lever, since the three segments and the complementary segments on the shaft 2'! are of different radii. The return of the lever to a central position from any one of the gearselecting positions returns the camshaft to its neutral position.

In the example illustrated first and second gears are selected by angular movements of the rocking shaft 2'! of approximately 24 to opposite sides of the neutral position, and these gears are selected by moving the gear lever in a plane at right angles to the axis of the spindle 23 while the head 16 lies in the fork IS on the middle segment 2|, this segment being of substantially the same radius as the segment 25 on the shaft 2! with which it meshes.

The positions of the various parts corresponding to the selection of first and second ears are shown in dotted lines and in full lines respectively in Figure 5.

Third and fourth gears are selected by angular movements of the shaft 27 of approximately 12 to opposite sides of the neutral position and to select these gears the gear lever is rocked over to engage the head I 6 with the fork l! on the segment 20 meshing with the segment 24 on the shaft 21, the segment 20 having a gear ratio with the shaft which is half that of the segment 21, so that the same angular movement of the gear lever now only moves the shaft 27 through half the angle.

Reverse gear is selected by an angular movement of the shaft 21 to one side of neutral of approximately 36, and to select reverse the gear lever is rocked over against the resistance of the plunger 38 to engage the head 16 in the fork [9 of the third segment 22 which is of greater radius than the segment 26 on the shaft 27 with which it meshes so that an angular movement of the gear-lever of the same amplitude as before moves the lever arm 29 into the position shown in Figure '7 and hence moves the camshaft into one extreme position.

The different positions of the free end of the lever arm 20 corresponding to the selection of the different gears are indicated in Figure and. the corresponding positions of the knob of the gear-lever are shown diagrammatically in Figure 3.

From Figure 3 it will be clear that the movement of the gear lever to either side of neutral required for the selection of any gear is constant and that the movements given to the lever in selecting the gears are the same as those which would be given to the lever of an ordinary layshaft gear-box.

The lever passes through neutral position in moving from any one gear-selecting position to another and it is resiliently located in the neutral positions and in each of the gear-selecting positions by the plunger 30 co-operating with the notched quadrant 32 so that there is no tendency for the lever to move under vibration.

If the gear-box has five forward speeds the same mechanism can be used by arranging one of the forward gear-selecting positions opposite to the reverse position.

If the mechanism is mounted under the steering wheel of the vehicle it may be difiicult or impossible to couple the lever arm 29 by direct linkage to the camshaft of the gear-box, and in that case the shaft 21 may be coupled to the camshaft by a flexible shaft or other convenient transmission member.

I claim:

1. Control mechanism for the selection of gears in an epicyclic gear-box by angular movement of a camshaft in the gear-box, comprisinga gearlever angularly movable about a fixed axis, an angularly movable shaft adapted to be coupled to the camshaft, gearing of different ratios, and means for selectively coupling the gear-lever to said shaft through said gearing whereby equal gear-selecting movements of the lever to opposite sides of a neutral position effect angular movements of said shaft and camshaft of different amplitudes.

2. Control mechanism for the selection of gears in an epicyclic gear-box by angular movement of a camshaft in the gear-box, comprising an angularly movable shaft adapted to be coupled to the camshaft, toothed segments of different radius on said shaft, complementary toothed segments in mesh with said segments and independently rotatable about a common axis parallel to said shaft, and an angularly movable gear-lever adapted to be selectively engaged with any one of said independently rotatable segments for moving it angularly about its axis and moving the shaft angularly through an angle dependent on the radius of the segment engaged by the lever relative to the radius of the segment on the shaft with which it meshes.

3. Control mechanism for the selection of gears in an epicyclic gear-box by angular movement of a camshaft in the gear-box comprising a housing, a shaft mounted for angular movement in the housing and adapted to be coupled to the camshaft, toothed segments of different radius integral with said shaft, complementary toothed segments in constant mesh with said segments and independently rotatable about a spindle in the housing parallel to said shaft, a fork integral with each of said independently rotatable segments, a gear-lever mounted for universal movement about a pivot in the housing, and a head on said lever adapted to be selectively engaged in any one of said forks by a rocking movement of said lever in one plane, angular movement of said lever in another plane effecting angular movement of the independently rotatable segment carrying the fork with which the head is engaged and said segment effecting angular movement of said shaft.

4. Control mechanism for the selection of gears in an epicyclic gear-box by angular movement of a camshaft in the gear-box comprising a gearlever angularly movable about a fixed axis, an angularly movable shaft adapted to be coupled to the camshaft, means for selectively coupling the gear-lever to said shaft through gearing of different ratios, and means for resiliently locating said gear-lever in positions corresponding to neutral and to the selection of different gears.

GLYN P. ROBERTS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 958,256 Koons May 17, 1910 1,820,006 Beringer Aug. 25, 1931 FOREIGN PATENTS Number Country Date 23,426 Great Britain Oct. 23, 1907 649,573 Germany Aug. 27, 1937 

